1. Technical Field
The disclosure relates to a liquid phase deposition apparatus, and particularly to a chemical bath deposition (CBD) apparatus.
2. Related Art
CBD is a liquid phase deposition process widely used in many industries at present. The most common CBD is conducted in a chemical tank. However, the volume of the chemical tank is quite large, and thus large amount of chemical plating solution must be used, leading to a decreased solution utilization, which not only causes a high deposition cost, but also incurs a major problem of wastewater treatment. Another CBD is to locate a substrate to be deposited in a crucible with a surface facing upward, and then pour a solution into the crucible to cover the substrate to be deposited, so as to perform the deposition. However, in the deposition process, the plating solution is also deposited on the crucible, which not only lowers the plating solution utilization, but also increases the process time because the crucible is required to be cleaned after deposition. For example, for the fabrication cost of a Cu(InGa)Se2 (CIGS) solar cell, a buffer layer plays a very important role. In case that a CdS buffer layer with a thickness of 50 nm is fabricated through a traditional CBD, the cost thereof accounts for 20% (excluding a substrate) of the cost of the cell, and thus the fabrication cost of the cell can be greatly lowered if the disadvantage can be effectively alleviated. In addition, in the traditional CBD, accompanying the cluster-cluster growth mechanism, ions in the solution form solid particles in the solution first, and then are adhered to the solid substrate, so that the formed film is opaque, uneven, and poor in adhesion. Therefore, if nucleated particles on the substrate can be removed effectively, the cell efficiency can be effectively improved.